Her partner of almost 40 years - writer, broadcaster and rugby commentator David Parry-Jones - was diagnosed with Alzheimer's in 2009. Here Beti shares a flavour of their life together.

His name was on the envelope - and of course he opened it. If I get to the post first and see an official looking letter addressed to David Parry-Jones, I open it to avoid the kind of confrontation that happened this morning.

"This letter says that the money belongs to me," he says. And with hackles rising he adds: "So where is it?"

"It's in your account in the bank", I say, "to use as and when you need help."

He doesn't understand "bank account" any more. He'd banked at our local little HSBC bank for decades. When his driving licence was taken away, I carried on with the routine and took him there every Thursday.

The staff knew him well and had followed his decline with great concern and sympathy. But the branch closed. He would have been completely lost in a bigger largely automated branch. So now I get money "from the wall" - which he finds totally ridiculous - he never used an ATM service.

I could say to him, I suppose, that as his carer I should be pocketing the £53, But that would really get him going - "It's mine not yours!" He doesn't understand I'm one of the unpaid carers who save the state £8 billion a year.

Beti George and David Parry-Jones (photo: Warren Orchard)

He'd dressed himself this morning, but then his anxiety about the money led him into a paddy and he decided to take off his shirt. "Please leave it on," I said. But he was angry and I said OK and yes - stormed off to the study. Five minutes later he was calling softly - "Apology. Accepted?"

"Of course," I said - and gave him a hug. "Do you love me a little?" he says. "I must do, or else I wouldn't be here - because you can be difficult." "Yes I know. It's the heat - up here," he says, tapping his head.

(I wish I were a scientist working on research into dementia - trying to follow every twist and turn of those wires in the brain. Living with someone with dementia gives one an intense insight into the behavioural aspects of the disease which cannot be described easily and in detail to a researcher asking pre-formulated questions.)

David's hair was in a mess - and I laughed and told him to go and take a look in the mirror. He came back in a good mood having combed his hair.

It's the Saturday morning after Lady Thatcher's death, and The Guardian has a spoof story on Lady Thatcher written by Posy Simmons - King Ironsides. He's amused by the caricature pictures of the Iron Lady. I tell him to read it so that he could decide whether she was worthy of his adoration. We laugh again.

It strikes me why more hasn't been done about how the brain of this powerful woman had been destroyed by dementia - and that it's a disease that desperately needs to be tackled before it overcomes us, leaving state and society unable to cope financially and emotionally.